Approach to a Child with Coma Prof Rashmi Kumar Department of Pediatrics, KG Medical University, Lucknow

Coma: Definition Derived from the Greek word ‘Koma’ or deep sleep Various grades – ‘spectrum’ State of altered consciousness with reduced capacity for arousal and reduced responsiveness to visual, auditory and tactile stimulation

The word coma should be differentiated from Syncope (transient alteration of consciousness) Seizure

Coma : Pathophysiology Normal consciousness is maintained by integrity of certain areas of the cerebral cortex, thalamus and brain stem Altered consciousness due to Diffuse lesions of cerebral cortex (metabolic, toxic, hypoxic) Focal lesions of ARAS - central core of brain stem

Coma: Pathophysiology Diffuse insult to both cerebral hemispheres (metabolic/toxic/hypoxic/ischemic) or focal lesion affecting ascending reticular activating system (ARAS) located in upper pons, midbrain & diencephalon. Affected by compression (herniation) Lesion in one cerebral hemisphere will not produce coma ICT generalised ischemia (CPP=MAP-ICT) focal ARAS damage by herniation

Coma: Pathophysiology Diffuse bilateral cerebral lesion Mass lesion compressing ARAS

Coma: Etiology CNS Causes: Structural CNS infections Mass lesions  CSF obstruction +  volume Trauma Vascular CNS Causes: Functional Seizures Hypoxic - ischemic injury

Coma: Etiology Extracranial causes Metabolic Systemic shock hypo/ hypernatremia hypoglycemia diabetic coma hepatic uremic hypoxia Reye’s Respiratory failure Acidosis/ alkalosis Hyperosmolality Inherited metabolic disorders

Coma: Etiology Extracranial causes Drugs Iron Salicylates aceraminophen Metals Barbiturates benzodiazepines opioids tricyclics antihistamines

Coma: Etiology Extracranial causes Toxic Lead gram negative endotoxemia Shigella CO poisoning pesticides alcohol/ ethylene glycol

Coma: Etiology Extracranial causes Endocrine Miscellaneous Psychogenic hypothyroidism diabetic Miscellaneous hypertensive encephalopathy heat stroke hypothermia Psychogenic

Coma: Immediate Management Is resuscitation required? A – airway  prevent tongue falling back, suction B – breathingrespiratory support, oxygen C- circulationiv fluids, monitor BP, vasopressors If any evidence of poisoning  GL

Coma : Quick History & Examn Circumstances? Duration & onset? Acute in CNS infection, trauma, seizure, poisoning, metabolic, vascular H/o poisoning? H/o trauma? H/o fever? H/o seizure? Past medical history H/o seizures in the past? H/o known endocrine disorder? H/o headache/vomiting/visual symptoms?

Coma: Quick History & Examn Vitals Fever BP S/o shock S/o  ICP bradycardia, hypertension Respiration  rapid in acidosis & CNS lesions also General Physical: Evidence of trauma, injury, tongue bite Jaundice Breath - for odor of ketones, fetor hepaticus etc Skin peticheae, exanthem Dry, flushed skin in belladonna poisoning Moist skin with salivation in organophosphorus poisoning Complete systemic exam

Coma : Neurological Examn Painful stimuli- strong pinch, pressure on nail bed, pressure on globe Glasgow Coma Scale: Best Motor Best Verbal Eye opening 1. none none none 2. extension to incomprehensible to pain pain sounds 3. flexion to inappropriate to call pain words 4. withdraws confused speech spontaneous 5. localises well oriented 6. Moves on command

Coma : Neurological Examn Modified Coma Scale for children < 2 yrs Best Motor Best Verbal Eye opening 1. none none none 2. extension to moaning to to pain pain pain 3. flexion to crying to to call pain pain 4. withdraws irritable cry spontaneous 5. localises coos, babbles 6. Moves on command

Coma : Neurological Examn Meningeal signs Tone/posturing Decerebrate- lesion in upper pons Decorticate- b/l cortical lesion with preservation of brain stem function Flaccidity – when all cortical & brain stem function till pontomedullary junction are lost Fundus Pupils Pinpoint in pontine lesions/morphine poisoning B/l fixed dilated in terminal state, severe ischemic damage, atropine/belladonna poisoning U/l unreactive pupil ? transtentorial herniation Pupils generally small, equal & reactive in toxic/metabolic causes

Coma : Neurological Examn Cranial nerves 6th nerve palsy – false localizing sign u/l 3rd – impending herniation Deficits – suggest lesion in brain S/o ICP hypertension/bradycardia/abnormal breathing (Cheyne Stokes, hyperventilation, apneustic, ataxic) papilledema posturing cranial nerve palsies Brain stem reflexes: Doll’s eye response Oculovestibular reflex Corneal reflex

Structural vs functional coma Meningeal signs Focal deficits Brain stem reflexes lost Pupils unequal or fixed dilated Absent Present Semidilated and reactive

Coma: Investigations Counts Blood glucose, urea, electrolytes, acid base Ammonia, liver function, lactate Toxicology Lumbar puncture – CI if ICP. Abnormal in CNS infections Cultures EEG – usually non specific Imaging – r/o mass lesion

Coma: Treatment Treat the cause Supportive care – antipyretics, anticonvulsants Management of ICP Mannitol – 0.25 – 1 gm/kg of 20% solution (1.25 – 5 ml/kg) bolus iv Frusemide Diamox, glycerine Steroids – esp vasogenic edema Hyperventilation  lowers CBVCPP Maintain PCO2 between 25 – 30 mm Hg Nursing care: Position Nutrition Care of eyes Care of skin Chest physiotherapy Care of bowel & bladder Physiotherapy

Persistent vegetative state: patients after recovery from coma return to a wakeful state without cognition/ awareness of environment Children who remain in this state for > 3 months do not regain functional skills Causes – anoxia/ischemia/metabolic/encephalitic coma/head trauma Survival indefinite with good nursing care

Coma: Diagnosis of Brain Death Importance (American Academy of Neurology, 1995) Prerequisites: Cessation of all brain function Proximate cause of brain death is known Condition is irreversible Cardinal features: Coma Absent brain stem reflexes Pupillary light reflex Corneal reflex Oculocephalic Oculovestibular Oropharyngeal Apnea Confirmatory tests (optional) Cerebral angiography Electroencephalography Radioisotope cerebral blood flow study Transcranial Doppler ultrasonography 2 examinations – interval depends One/two physicians

Apnea Test Prerequisites:- Core temperature > 36.5O C (97o F). - Systolic blood pressure > 90 mm Hg (Adults only). - Euvolemia (or positive fluid balance in the previous 6 hours). - Normal PCO2 (or arterial PCO2 > 40 mm Hg). - Normal PO2 (or preoxygenation to obtain arterial PO2 > 200 mm Hg). Connect a pulse oximeter. Disconnect the ventilator or place the patient on CPAP at an appropriate level or place a cannula at the level of the carina and administer 100% O2 endotracheally at 8L per minute. Look closely for respiratory movements abdominal or chest excursions that produce adequate tidal volumes).- Measure arterial PO2 , PCO2 , and pH after approximately 8 minutes (10 minutes for children). Resume mechanical ventilation. Absence of spontaneous respiratory effort with PCO2 20 mm Hg > baseline (PCO2 > 60 mm Hg) confirms apnea and supports the diagnosis of death. If respiratory efforts are present, the test is inconsistent with brain death and should be repeated. For children, if the rise in PCO2 fails to reach 60 mm Hg, perform the test again for a duration of 15 minutes.- If the blood pressure becomes unstable or significant oxygen desaturation and cardiac arrhythmias are present during testing, resume ventilation. Immediately draw an arterial blood sample. If PCO2 > 60 mm Hg or the increase is 20 mm Hg > baseline normalized PCO2, the apnea test is consistent with brain death. If not, the result is indeterminate. A confirmatory test may be useful.

A. History: determine the cause of coma to eliminate remediable or reversible conditions B. Physical examination criteria: 1. Coma and apnea 2. Absence of brain stem function (a) Mid-position or fully dilated pupils (b) Absence of spontaneous oculocephalic (doll's eye) and caloric-induced eye movements (c) Absence of movement of bulbar musculature, corneal, gag, cough, sucking and rooting reflexes (d) Absence of respiratory effort with standardized testing for apnea 3. Patient must not be hypothermic or hypotensive 4. Flaccid tone and absence of spontaneous or induced movements excluding activity mediated at spinal cord level 5. Examination should remain consistent for brain death throughout the predetermined period of observation

Observation period according to age: 7 days to 2 months: Two examination and EEGs 48 hours apart 2 months to 1 year: Two examination and EEGs 24 hours apart or one examination and an initial EEG showing ECS combined with a radionuclide angiogram showing no CBF. More than 1 year: Two examinations 12 to 24 hours apart; EEG and isotope angiography are optional (No criteria for neonates < 7days of age)

MCQ 1. Cerebral Perfusion Pressure equals: a)      Mean arterial pressure + intracranial pressure b)      Mean arterial pressure - intracranial pressure c)       Intracranial pressure – Mean arterial pressure d)      None of the above

2. The following is true about Glasgow Coma Scale: a) The highest score is 10 b) Lowest score is 3 c) There are 5 possible scores for Best Motor Response d) Lowest score is 0

Unilateral unresponsive pupil is found in: a) Morphine poisoning b) Impending trantentorial herniation c) Belladona poisoning d) Brain death

A 7 year old child is brought to the emergency in coma A 7 year old child is brought to the emergency in coma. On deep painful stimulus there is no verbal response, no eye opening and slight extension of limbs. What is his Glasgow Coma Score? a) 7 b) 9 c) 5 d) 4

Signs of raised intracranial tension include all except: a) Hypertension b) Shallow breathing c) Bradycardia d) Papilledema

Prerequisites for diagnosis of brain death include all except: a) Cessation of all brain function b) Flat EEG c) Proximate cause of coma is known d) Condition is irreversible

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